docs: def connected(self):
          """
          Returns :py:data:`True` if the graph's every node can be reached from every
          other node.
          """
          node_list = self.node_list()
          for node in node_list:
              bfs_list = self.forw_bfs(node)
              if len(bfs_list) != len(node_list):
                  return False
          return True